package com.mapflow.util;

import org.apache.commons.beanutils.ConversionException;
import org.apache.commons.beanutils.Converter;
import org.apache.commons.lang.StringUtils;

import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * This class converts a java.util.Date to a String and a String to a java.util.Date.
 * 
 * @author <a href="mailto:matt@raibledesigns.com">Matt Raible</a>
 * @author <a href="mailto:tstrausz@tryllian.nl">Tibor Strausz</a>
 */
public class DateConverter implements Converter {

  /**
   * Convert a date to a String and a String to a Date
   * 
   * @param type
   *          String, Date or Timestamp
   * @param value
   *          value to convert
   * @return Converted value for property population
   */
  @SuppressWarnings("rawtypes")
  public Object convert(final Class type, final Object value) {
    if (value == null) {
      return null;
    }
    else if (type == Timestamp.class) {
      return convertToDate(type, value, DateUtil.getDateTimePattern());
    }
    else if (type == Date.class) {
      return convertToDate(type, value, DateUtil.getDatePattern());
    }
    else if (type == String.class) {
      return convertToString(value);
    }

    throw new ConversionException("Could not convert " + value.getClass().getName() + " to "
      + type.getName());
  }

  /**
   * Convert a String to a Date with the specified pattern.
   * 
   * @param type
   *          String
   * @param value
   *          value of String
   * @param pattern
   *          date pattern to parse with
   * @return Converted value for property population
   */
  protected Object convertToDate(final Class<?> type, final Object value, final String pattern) {
    final DateFormat df = new SimpleDateFormat(pattern);
    if (value instanceof String) {
      try {
        if (StringUtils.isEmpty(value.toString())) {
          return null;
        }

        final Date date = df.parse((String) value);
        if (type.equals(Timestamp.class)) {
          return new Timestamp(date.getTime());
        }
        return date;
      }
      catch (final Exception e) {
        throw new ConversionException("Error converting String to Date", e);
      }
    }

    throw new ConversionException("Could not convert " + value.getClass().getName() + " to "
      + type.getName());
  }

  /**
   * Convert a java.util.Date or a java.sql.Timestamp to a String. Or does a toString
   * 
   * @param value
   *          value to convert
   * @return Converted value for property population
   */
  protected Object convertToString(final Object value) {
    if (value instanceof Date) {
      DateFormat df = new SimpleDateFormat(DateUtil.getDatePattern());
      if (value instanceof Timestamp) {
        df = new SimpleDateFormat(DateUtil.getDateTimePattern());
      }

      try {
        return df.format(value);
      }
      catch (final Exception e) {
        throw new ConversionException("Error converting Date to String", e);
      }
    }
    else {
      return value.toString();
    }
  }
}
